Print in TPU or other flexible material of your choice. I have not tried this with a hard plastic.
Use 0.2mm layers or thinner. This will ensure 2 layers for the flat body.
Infill can be as little as 5% or much higher if you're looking for a stiffer ring.
The file in the image is the 200mm Diameter. I've added two more depending on the bed size of your printer. If there's another size you would like please let me know.